A group of IVR researchers have published the first single-cell investigation of central macula versus peripheral retina, from three human donors.
The expression profiles from more than 8000 individual cells were evaluated as part of this study. The inclusion of the central macular region of the retina in this experiment was critical, as this cone-rich region is the center of visual field, where our visual acuity is highest. Retinal organization in the central macula is arranged to minimize the dispersion of the incoming light, and to maximize the ability for high-resolution vision. Because high acuity vision derives from the fovea (central macula) changes in structure and expression in the central photoreceptors is critical to understand and reproduce for future cell-based therapies.
Several interesting genes and gene families were found to be expressed at different levels in the central macular region. These include transferrin (TF), which has been associated with age-related macular degeneration pathogenesis, was enriched in peripheral samples. A total of 148 genes were differentially expressed between cone photoreceptors from the fovea versus those derived from peripheral samples. Interestingly, peripheral cones were enriched for the gene encoding Beta-Carotene Oxygenase 2 (BCO2). A relative deficiency of this enzyme may account for the accumulation of carotenoids responsible for yellow pigment deposition within the macula.
Overall, this data set provides rich expression profiles of the major human retinal cell types and highlights transcriptomic features that distinguish foveal and peripheral cells.